A conventional cellular network (for example, an LTE network) is a single-hop network using a base station as a center, that is, data is directly interactively transmitted between the base station (eNB, Evolved Node Base Station) and a user equipment (UE, User Equipment). After a relay node (RN, Relay node) is introduced into an LTE-A protocol, multi-hop transmission exists in the interactive transmission of data between the base station and the user equipment, that is, the interactive transmission of data between the base station and the user equipment is required to pass through the relay node RN. As shown in FIG. 1, in an LTE-A network after the relay node RN is introduced, a transmission link between the user equipment and the base station may be divided into two segments, that is,
an access link Uu, which is an air interface link between the user equipment and the directly associated relay node RN; and
a relay link Un, which is an air interface link between the relay node RN and the base station eNB.
In an existing LTE network, in order to ensure quality of service (Qos, Quality of Service) of multi-service, a traffic bearer mapping mechanism is introduced. The bearer mapping of the traffic data flow in an LTE network is as shown in FIG. 2, where the LTE network includes a user equipment 1, a base station 2, a serving gateway (S-GW, Serving Gateway) 3, and a packet data network gateway (P-GW, PDN Gateway) 4. A Un radio bearer (Uu RB, Uu Radio Bearer) 5, an S1 bearer 6, and an S5/S8 bearer 7 that correspond to the user equipment 1 form an evolved packet system (EPS, Evolved Packet System) bearer. Trapezoid frames in the user equipment 1 and the packet data network gateway 4 represent a traffic flow template (TFT, Traffic Flow Template) operation.
An uplink traffic bearer mapping process in the existing LET network is as follows: The user equipment 1 maps the uplink traffic flow to an EPS bearer through an uplink traffic flow template (UL TFT, Uplink Traffic Flow Template); a one-to-one mapping between the UL TFT and the Uu radio bearer 5 is implemented by the user equipment 1 creating a binding between the uplink traffic data flow and the Uu radio bearer 5; a one-to-one mapping between the Uu radio bearer 5 and the S1 bearer 6 is implemented by the base station 2 creating a binding between the Uu radio bearer 5 and the S1 bearer 6; and a one-to-one mapping between the S1 bearer 6 and the S5/S8 bearer 7 is implemented by the S-GW creating a binding between the S1 bearer 6 and the S5/S8 bearer 7. Finally, the EPS bearer that transmits the data is cascaded by the Un radio bearer 5, the S1 bearer 6 and the S5/S8 bearer 7 and implements that the user equipment 1 supports a PDN connecting service between external PDN networks, thereby ensuring the QoS of multi-service. The relationships among the Uu radio bearer 5, the S1 bearer 6, and the S5/S8 bearer 7 are one-to-one mapping relationships.
As for the LTE-A network after the relay node RN is introduced, a Un radio bearer (Un RB, Un Radio Bearer) configured to support relay transmission exists on the relay link. The bearer mapping solution of the traffic flow in the existing LTE network cannot implement the transmission of the traffic data flow in the LTE-A network after the relay node RN is introduced, and therefore the QoS of the multi-service cannot be ensured.